Induction Heated Hair Styling Appliances And The Heating Unit Therefor

ABSTRACT

A heated hair-styling appliance for styling hair through heat is provided. The heated hair-styling appliance comprises a heating head having an outer shell covering at least part of the surface thereof, and an inner heat source core disposed within the inner part of the heating head, and a handle attached to a distal end of the heating head. The heated hair-styling appliance works in conjunction with an independent heating unit to heat up the inner heat source core, and the heat source core operationally supplies heat to heat up the outer shell for styling hair after it is being heated. A induction heating unit therefor is also provided.

FIELD OF THE INVENTION

The present invention generally relates to heated brush. Moreparticularly, the present invention relates to a heated brush for hairstyling and a heating unit for heating up the heated brush.

BACKGROUND

Hair styling often requires heating up hair to style it. Depending onthe used, different hair styling appliances have different ways ofheating up. For example, curling tongs and hair straightening device,such devices requires electrical power to continuously heating up theheating elements thereon. Most commonly, the electrical power issupplied through a power cord/wire connected thereto. Such powercord/wire often get in the users' way when they operate theseappliances.

Another hair styling appliance includes thermal brush that is commonlyused in conjunction with a hair blower/dryer. The hair blower/dryerserves as a heat source to heat up hair as well as the thermal brushoperationally. It is recognized that ordinary users may face challengesto operate several appliances simultaneously. Further, such appliancesdo not retain heat within the appliances itself; as soon as the hairblower stops blowing heated air to the thermal brush, it cools down veryquickly.

There is a desire to provide user a cordless and handheld appliance thatis easy and convenience to use. Preferably, the cordless and handheld iseasy to operate, fast heating up,

In one aspect of the present invention, there is provided a heatedhair-styling appliance for styling hair. The hair-styling appliancecomprises a heated head having an outer shell covering at least part ofthe surface thereof, and an inner heat source core disposed within theinner part of the heating head, a handle attached to a distal end of theheating head. The hair-styling appliance works in conjunction with anindependent induction-heating unit to heat up the inner heat sourcecore, wherein the heat source core supplies heat to heat up the outershell for styling hair after it is being heated.

In one embodiment, the handle is detachable from the heating head.

In another embodiment, wherein the outer shall is made up of metal.Possibly, the outer shell is cover by a thermal insulation layer, suchas ceramic coating or any thermal insulation material. In yet anotherembodiment, the inner heat source core is made up of a thermalconducting material, such as ferrous metal.

In a further embodiment, the hair-styling appliance is a thermal brush.The thermal brush may have the outer shell covered with a thermalinsulation layer, and bristles are formed on the thermal insulationlayer.

In yet a further embodiment, the hair-styling appliance is a curlingtong or a hair-straightening iron.

In another aspect of the present invention, there is provided a hairstyling appliance comprises an induction heating unit having acontainer, the container defines a well that is surrounded by ainduction coil winding, the induction coil winding is connected to acircuitry operationally generates electromagnetic induction within thewell through the coil winding and the aforesaid hair-styling appliance.The hair-styling appliance is heated up within the well through theelectromagnetic induction for usage.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments according to the present invention will now bedescribed with reference to the figures accompanied herein, in whichlike reference numerals denote like elements;

FIG. 1A illustrates an overall appearance of a heating unit inaccordance with one embodiment of the present invention;

FIG. 1B illustrates the heating unit of FIG. 1A, with a portion of thehousing cut out, exposing the components mounted within the heatingunit;

FIG. 1C illustrates a heating pot in accordance with an alternativeembodiment of the present invention;

FIG. 2 illustrates a schematic diagram of the circuitry of the heatingunit in accordance with one embodiment of the present invention;

FIG. 3 shows an operation flow of the induction-heating unit of FIG. 1Ain accordance with one embodiment of the present invention;

FIG. 4 illustrates a thermal hairbrush in accordance with one embodimentof the present invention;

FIG. 5A illustrates a thermal hairbrush in accordance with anotherembodiment of the present invention;

FIG. 5B illustrates a thermal hairbrush in accordance with a furtherembodiment of the present invention;

FIG. 6 illustrates a curling iron in one embodiment of the presentinvention; and

FIG. 7 illustrates a hair-straightening appliance in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention shall now be described in detail,with reference to the attached drawings. It is to be understood that nolimitation of the scope of the invention is thereby intended, suchalterations and further modifications in the illustrated device, andsuch further applications of the principles of the invention asillustrated therein being contemplated as would normally occur to oneskilled in the art to which the invention relates.

FIG. 1A illustrates an overall appearance of a heating unit 100 inaccordance with one embodiment of the present invention. The heatingunit 100 is adapted to heat up a thermal brush (not shown in FIG. 1A).Preferably, the heating unit 100 is adapted with induction heatingassembly for heating up the thermal brush placing therein. The heatingunit 100 includes a housing 101 for accommodating components therein. Anupper portion of the housing 101 incorporates a well 103 adapted forloading the heated brush. The size and depth of the well 103 is cateredto be large enough for loading multiple sizes thermal brushes. Theheating unit 100 is adapted for heating up thermal brush that generallyadapted with handle. It is also desired that the well is adapted toreceive only the brush portion of the thermal brush, while exposing thehandle for outside of the heating unit for handling. Accordingly, athermal brush can easily be placed into the well 103 so that the heatedbrush can be heated through the heating unit 100 for subsequent usage.Further, the thermal brush, regardless of the sizes, can be effortlesslyplaced or dropped the heated brush into the well 103 at any orientationswhile the heating unit is heating up the heated brush within the cavityof the well 103. A control panel 105 can be disposed on an externalsurface of the housing 101. The control panel 105 may further include abutton 106 and a display screen 107 for providing the necessarilyoperation control. The button 106 may be an on/off switch, ormulti-triggering button for controlling the operation of the heatingunit.

It is understood that an induction heating unit is desired in thisembodiment as it offers quick heat up time and it allows the hairstyling appliances to be reheated with minimal or no downtime. However,other heating unit may be desired without departing from the scope ofthe present invention.

FIG. 1B illustrates the heating unit 100 of FIG. 1A, with a portion ofthe housing 101 cut out, exposing the components mounted under thehousing 101. The heating unit 100 comprises two parts, an upper partthat includes the well 103, and a bottom part that accommodates thecircuitry of the heating unit 100.

The upper part of the heating unit 100 includes the well 103, a windingroller 111 and a coil 112. The winding roller 111 is an inner cylinderadapted to wrap around the circular surface of the well 103 withinhousing 101. The winding roller 111 facilitates a means for supportingthe coil 112, such that the coil of wire, preferably copper wire, can bedisposed around the perimeter of the winding roller 111.

The coil 112 is electrically connected to the circuitry of the heatingunit 100, which is mounted beneath the upper part of the heating unit100. The circuitry comprises a PCB board 114 and components adapted fordriving the coil 112 to generate the electromagnetic induction to heatup the heated brush. Beneath the PCB board 114, there is furtherprovided a heat sink 116 attached to the components that operationallyproduce heat. In another embodiment, the heating unit 100 may furtherprovide a fan for increase the heat dissipation efficiency.

FIG. 1C illustrates an induction-heating pot 150 in accordance withanother embodiment of the present invention. The induction heating pot150 has a similar configuration as that of the induction-heating unit100. The induction heating pot 150 further comprises a guiding pole 152extending upwardly from the bottom of the well. The guiding pole 152 hasa tapered end and along the length of the guiding pole 152, there isprovided a thermal sensor 155. The induction heating pot 150 works inconjunction with a thermal brush or hair-styling appliances adapted witha corresponding slot configured for receiving the guiding pole 152.Preferably, the guiding pin 152 is supported through a flexible memberallowing the guiding pin to be able to swivel in all direction.

FIG. 2 illustrates a schematic diagram of the circuitry of the heatingunit in accordance with one embodiment of the present invention. Thecircuitry 300 includes a microcontroller 302, an insulated gate bipolartransistor (IGBT) driver 304, one or more IGBT 306, a power source 310,an interface panel 314, sensors 316, and optionally a fan 320. The powersupply 310 operationally supplies power to the entire heating unit. Itmay be a multi-voltage power supply. Depending on the design andspecification, the power supply may further include a switch mode powersupply (SMPS) circuit, to transforms the DC bus voltage into severaldifferent DC low voltage outputs.

The microcontroller 302 is adapted for controlling the entire operationsand processes of the induction-heating unit. The microcontrollers 302suitable for the induction heating equipment can be any suitablemicrocontroller available in the market.

The IGBT 306 is the main power component and is provided to drive thecoil 308 that are winded around the well of the induction heater. TheIon 306 is driven by the IGBT driver 304 that provides a voltagetransfer interface between the microcontroller 302 and the IGBT 306. Itis well known in the art that, when desire, the IGBT 306 can be replacedseveral bipolar transistors.

The microcontroller is further connected to the interface panel 314 forreceiving control input from user and display some operating status tothe user. The interface panel 314 may include switches and a displaypanel. User may control the operations of the induction heater throughthe switches provided on the control panel, and monitor the operatingstatus through the display panel. The interface panel 314 may furtherinclude LED lights for showing the operating status.

The sensors 316 include a thermal sensor for detecting the temperaturewithin the well of the induction heater, or more specifically thetemperature of the thermal brush heated therein. These sensors detectthe necessary operating status automatically, and the microcontroller302 responds according. For example, the weight sensor can be placed atthe bottom of the well as a switch covering the entire bottom surface,and when a thermal brush is placed within the well, the inductionheating unit would recognize so in order to carrying our furtheroperation. This can prevent that the induction heating being turned onunintentionally without any thermal brush presents therein. In anotherembodiment, the weight sensor can be used to detect the presence of thethermal brush to automatically trigger the induction-heating unit toheat up the thermal brush as it is placed within the well of the heatingunit.

For safety purpose, it would be desired that the thermal sensor beprovided for detecting the heating condition. Preferably, the thermalsensor is adapted to be able to detect at least the temperature of thethermal brush. When the thermal brush is detected overheating, theinduction-heating unit will cut off automatically. For example, when aheated thermal brush that has not been cooled down is placed withinwell, the induction heater may overheat the thermal brush. Accordingly,it is desired that the temperature of the thermal brush that is placedwithin the well can be detected before the induction heating operationstarts.

The thermal sensor may be a thermopile, or thermopile infrared sensor orthe like. It may also be thermocouples or the like. Most preferably, thethermal sensor is able to detect the temperature of the thermal brushcontactlessly.

The induction-heating unit may further adapt with the fan 320 todissipate heat during the heating operation. The heat generatingcomponents may further attach with heat sink to work in conjunctionswith the fan to effectively dissipate the heat operationally.

It is understood to a skilled person that the above circuitry isillustrated by way of example only, not limitations. There are manyother suitable configurations that can be adapted for theinduction-heating unit. Preferably, the induction-heating unit shall beable to heat up the heated element of the thermal brush to a desiredworking temperature suitable for practical hair styling. The thermalsensor can be adapted to control or cut off heating to preventoverheating.

The induction heater is heated by controlling the coil power. To controlit, a synchronous signal is needed to be detected.

For safety protection, the induction may provide an overvoltage (OV) andovercurrent (OC) detection means. Operationally, when the inductionheater is running, it may generate an over voltage or a high level ofvoltage noise created by the repeatedly switching (i.e. on/off) IGBT306, which may damage the IGBT 306. A potentiometer OV may befacilitated to the microcontroller 302 to regulate the voltage. Whencurrent flowing through the IGBT 306 is higher than the expectedcurrent, the IGBT 306 can also be damaged. A current transformer can beadapted to prevent OC.

FIG. 3 shows an operation flow of the induction-heating unit of FIG. 1Ain accordance with one embodiment of the present invention. Theoperation starts with pressing a power switch to turn on theinduction-heating unit at step 352. At this stage, the induction-heatingunit is placed at a standby mode. At step 354, the thermal brush can beinserted into the well of the induction-heating unit. Once the thermalbrush is placed in the induction-heating unit, the induction-heatingunit will detect the presence of the thermal hairbrush through theweight sensor at step 356. The presence of thermal hairbrush willtrigger a thermal sensor to detect whether the temperature of thethermal hairbrush is detected to be higher than a predefined level. Ifthe detected temperature is higher than the predefined level, theinduction-heating unit will not function to heat up the thermalhairbrush. Such detection is provided to prevent overheating. If thedetected temperature is below the predefined level, the LED lightindicator may light up to indicate that the induction-heating unit isready for operation. At step 358, the user may press a start button tostart heating up the thermal hairbrush. At step 360, theinduction-heating unit may determine the heating time require. The timedetermination may be based on the temperature detected at step 356, orit triggers the sensor to detect the temperature again after the startbutton is pressed. The thermal hairbrush is being heated up in step 362,and once the heating operation is completed at step 364, users mayremove the thermal hairbrush from the induction-heating unit at step 366for hair styling.

FIG. 4 illustrates a thermal hairbrush 400 in accordance with oneembodiment of the present invention. The thermal hairbrush 400 isadapted with a capability of storing and self-releasing heat without anypower source or external heat source. The thermal hairbrush 400 isadapted for heating up through induction heating unit, and once heatedup it can be used immediately out from the induction-heating unit. Thethermal hairbrush 400 has a brush head 402 with a brush handle 404thereto for allowing users to handle the thermal hairbrush 400. Thebrush head 402 is shown in a preferred embodiment as a round ventedbrush of a generally elongated cylindrical shape. However, one skilledin the art should appreciate that the thermal hairbrush 400 may be usedwith a round brush, a cylindrical shaped brush, a flat hairbrush, apaddle brush, a spinning brush, a half round brush, a vent brush with aspecific configuration adapted to suit the present application. When inuse, user may hold on to the brush handle 404 and place it into the wellof the induction-heating unit of FIG. 1. Once it is heated, the heatedthermal hairbrush 400 may assist with curling the hair being brushedwith the heat emitted therefrom. The advantage of the thermal hairbrush400 is, once heated, it can be use immediately. It also does not requireexternal power source to heat it up, therefore, no cable is adaptedthereon, therefore, it is easier to handle.

Referring back to the FIG. 4, the brush head 402 may be formed in avariety of diameters. Relatively narrow diameters are especiallyeffective for creating curls while conversely relatively largerdiameters create looser curls. The brush head 402 is extends about halfway on the heated hairbrush 400 from an end to about a midpoint on thethermal hairbrush 400. The brush head 402 has a length suitable to combor style hair in a comfortable manner and further to have a adequatenumber of bristles 406 disposed in surrounding fashion thereon. Asillustrated by the thermal hairbrush 400, the bristles 406 are extendedfrom the inner side of the brush head 402.

The brush head 402 has a outer shell 408 that disposed around the brushhead 402 in concentric relation to the brush head 402. The outer shell408 further defines through holes 408, through which, the bristles 406extend outwardly from the inner space of the brush head 402.

Still referring to FIG. 4, the thermal hairbrush 400 is being shown witha cut out portion exposing the inner part of the brush head 402 and theconstructions of the outer shell 408. Generally, the outer shell 408 isadapted as a heat retainer. The outer shell 408 is made up of two layers412, 414. The layer 412 is made up of thermal insulation material andthe layer 414 is made up of thermally conductive material. For layer412, materials such as ceramic material, polymer may be adapted. In analternative embodiment, it may also be a thin layer of thermallyinsulation coating coated on top of the layer 414. The layer 414 on theother hand, is made up of thermally conductive material such as metal,copper, aluminum, or any other thermally conductive material known inthe art. Through the cut out portion, it can be seen that the thermalbrush 400 further comprises a heat source core 420, of which, thebristles are extended therefrom. Preferably, the heat source core 420 isalso made up of heat conducting materials. More preferably, the heatsource core 420 can be made up of ferrous metals or alloys. Thepreferred materials for the heat source core 420 shall be easily heatedup through induction heating, and preferably, the material used is ableto retain heat as long as possible. The heat source core 420 may furtherbe quoted with heat retaining coating, such as ceramic coating.

Operationally, the thermal brush 400 is placed in an induction-heatingunit, such as the one illustrated in FIG. 1A. Once the induction-heatingunit is turned on, the thermal brush 400 is being heated up throughelectromagnetic induction. More specifically, the conducting materials,i.e. the outer shell 408 and the heat source core 420 will be heated upto a desired temperature. The induction heating may be stopped through atimer, and once the time is up and the thermal brush 400 is heated up,it is ready to be used. When in used on hair, the outer shell 408 heatsup the hair directly because it is in direct contact with hair. Thethermally conductive layer 414, which is heated up by theinduction-heating unit, releases the heat through the thermal insulationlayer 412 slowly. The thermal insulation layer 412 serves as a thermalretainer for holding the heat onto the thermally conductive layer 414 aslong as possible.

Similarly, once the heat source core 420 is heated up by the inductionheating unit, it serves as a heat source to the thermal brush 400 forsupplying heat continuously to heat up the outer shell 408 as it loosesheat to the ambient operationally.

In yet another embodiment, the thermal insulation material can be alayer of insulating coating, for example, ceramic coating. Suchinsulation material can also be applied onto the heat course core 420,in accordance with another embodiment of the present invention.

FIG. 5A illustrates a thermal hairbrush 500 in accordance with anotherembodiment of the present invention. The thermal hairbrush 500 comprisesa brush head 502 with a brush handle 504 attached thereto at one end.The brush head 502 has a outer shell 508 that disposed around the brushhead 502 in concentric relation to the brush head 502. The outer shell508 is formed by two layers, a sleeve 510 and a metal layer 512. Themetal layer 512 is an inner cylinder defining an inner cavity. The metallayer is made up of thermal conductive material, such as copper,aluminum or the like. Preferably, it is made up of a material that canbe heated up through induction heater. The sleeve 510 is an outer layerwrapping around the metal layer 512. Bristles 514 of the thermalhairbrush 500 are extending directly from the sleeve 510. The sleeve 510together with the bristles 514 are made up of thermal insulationmaterial, for example, nylon.

Within the cavity of the inner cylinder, the brush head 502 is furtherprovided with a heat source core 520 disposed along the concentric axisof the brush head 502. In this embodiment, the heat source core 520 isconfigured as a solid component, though it is possible to make the heatsource core 520 with a hollow cylinder. Similarly, the heat source core520 is made up of thermal conducting material; more preferably, it ismade up of material that can be heated up through induction heating.

As shown in FIG. 5A, the heat source core 520 is disposed within thecavity spaced apart from the sleeve 510. In another embodiment, it ispossible that the heat source core 520 can be made as an inner cylinderdisposed beneath the metal layer 512, with or without space. In yet afurther embodiment, the heat source core 520 may also be covered by athermal insulating material (i.e. between the metal layer 512 and theheat source core 520) aims for slowing down the heat transfer from theheat source core 520 to the metal layer 512.

Operationally, the thermal hairbrush 500 is heated up with a same orsubstantially the same way as the thermal hairbrush 400, and as thethermal hairbrush 500 does not have holes on the outer shell as thethermal hairbrush 400, it is expected that the heat can be retainedlonger within the thermal hairbrush 500.

Although, the outer shells shown above are completely surrounding therespective brush head, alternatively the outer shells may only surrounda radial portion of the brush head such as three quarters of the brushhead, half of the brush head or a quarter of the brush head.

Further, the brush heads of the thermal hairbrushes illustrated aboveare fixed to the handle. In other embodiments, these thermal hairbrushesmay be adapted with the brush head detachable from the handle, whendesire. In such case, the handle may adapt a quick release latch forsecuring the brush head onto the handle.

FIG. 5B illustrates a thermal brush in accordance with an alternativeembodiment of the present invention. The thermal brush is substantiallythe same as the thermal brush 500 except that the heat source core 520is made a hollow core and the top of the thermal brush is adapted withan aperture leading up to the hollow space of the hollow core. Suchconfiguration allows the thermal brush to be placed into the inductionheating pot through inserting the guiding pole 152 into a hollow spaceof the hollow heat source core 520 as shown in FIG. 5B. Preferably, thethermal sensor 155 is made slightly bigger than the diameter of theguiding pole 152 to give a tight fit when it is inserted into the heatsource core of the thermal brush. Such configuration allows the thermalsensor to effectively measure the temperature of at least the heatsource core 520.

FIG. 6 illustrates a curling iron 600 in one embodiment of the presentinvention. The curling iron 600 comprises a handle 602 and an heatingrod 604 attached to the handle 602. The curling iron 600 further has aclamp 606 pivoted at the proximal end of the handle 602 with a clampingplate 607 covers a portion of the heating rod 604, and a actuator 608 onthe other side of the pivot projecting over the handle 602.

In FIG. 6, the front end of heating rod 604 is cut out to show the innerconfigurations of the heating rod 604. As shown, the heating rod 604includes a heat source core 612 and a heating shell 614. The heatingshell 614 forms the outer shell of the heating rod 604. When in used, itis directly contacting the hair to style the hair. The heating shell 614may be coated with a layer of thermal insulating material for prolongingthe heating process. The heat source core 612 is a concentric tubularcomponent that disposed within the heating shell in a telescopic manner.When possible, a space may be provided between the heat source core 612and the heating shell.

It is to be noted that the curling iron 600 does not require any powersource to operate, therefore, no cord is attached thereto.

FIG. 7 illustrates a hair-straightening appliance 700 in accordance withone embodiment of the present invention. The hair-straighteningappliance 700 includes two opposing tongs 702 that are being hingedtogether at one distal end. Opposite the hinge, the opposing tongs 702holds a heating plate 704 on each tong 702. The heating plate 704 isremovable from the tong 702. The heating plate can be a flat panel forstraightening hair, or a profiled panel defining zigzag profile forcrimping hair.

As shown in FIG. 7, the front end of the lower tong 702 is cut out toshow the inner configurations of the hair-straightening appliance 700.As shown, the tong 702 has a heat source core 712 disposed beneath theheating plate 704 with a space apart.

It is understood that the hinge of the two opposing tongs 702 can beconfigured at the middle, i.e. class 2 lever, in accordance with anotherembodiment of the present invention.

When in used, the curling iron 600 and the hair-straightening appliance700 illustrated above can be placed into an induction-heating unit forheating up. Once it is heated up to a desired temperature, it can beremove from the induction-heating unit for immediate usage. The outerplate or shell directly heats up the hair as it is in direct contactwith the hair. The inner core, which was also heated up through theinduction heating unit, dissipates it heat slowly to the outer plate orshell, thereby prolonging the heating capability.

While specific embodiments have been described and illustrated, it isunderstood that many changes, modifications, variations, andcombinations thereof could be made to the present invention withoutdeparting from the scope of the invention.

1. A heated hair-styling appliance for styling hair through heat, theheated hair-styling appliance comprising: a heating head having an outershell covering at least part of the surface thereof, and an inner heatsource core disposed within the inner part of the heating head, a handleattached to a distal end of the heating head; wherein the hair-stylingappliance works in conjunction with an independent heating unit to heatup the inner heat source core, wherein the heat source coreoperationally supplies heat to heat up the outer shell for styling hairafter it is being heated.
 2. The hair-styling appliance in accordancewith claim 1, wherein the handle is detachable from the heating head. 3.The hair-styling appliance in accordance with claim 1, wherein the outershall is made up of metal.
 4. The hair-styling appliance in accordancewith claim 1, wherein the outer shell is cover by a thermal insulationlayer.
 5. The hair-styling appliance in accordance with claim 1, whereinthe outer shell is coated with a ceramic coating.
 6. The hair-stylingappliance in accordance with claim 1, wherein the inner heat source coreis made up of a thermal conducting material.
 7. The hair-stylingapplicant in accordance with claim 6, wherein the inner heat source coreis made up of ferrous metal.
 8. The hair-styling appliance in accordancewith claim 1, wherein the hair-styling appliance is a thermal brush. 9.The hair-styling appliance in accordance with claim 8, wherein thethermal brush has the outer shell covered with a thermal insulationlayer, and bristles are formed on the thermal insulation layer.
 10. Thehair-styling appliance in accordance with claim 1, wherein thehair-styling appliance is a curling tong.
 11. The hair-styling appliancein accordance with claim 1, wherein the hair-styling appliance is ahair-straightening iron.
 12. The hair styling appliance in accordancewith claim 1, wherein the heating unit is an induction-heating unit. 13.A hair styling appliance comprising: an induction heating unit having acontainer, the container defines a well that is surrounded by ainduction coil winding, the induction coil winding is connected to acircuitry operationally generates electromagnetic induction within thewell through the coil winding; a heated hair-styling appliance inaccordance with claim 1, wherein the hair-styling appliance is heated upwithin the well through the electromagnetic induction for usage.
 14. Thehair styling appliance in accordance with claim 13, wherein theinduction heating unit comprising a guiding pole extending upwardly froma bottom surface of the well and a thermal sensor disposed along thelength of the guiding pole; and the heated hair-styling appliancecomprises a hollow inner heat source core and an aperture leading up tothe hollow space of the inner heat source core, wherein the hollow spaceis adapted to receive the guiding pole such that the thermal sensor isable to measure the temperature of at least the inner heat source core.